Optimising natural flood management benefits from peatland restoration

Across the world restoration of degraded peatlands involves manipulation of peatland hydrology. Often this includes blocking of drainage and changing of land cover types. These landscape scale interventions in the peatland system have the potential to significantly modify runoff from peatland systems and so to be incorporated into schemes of natural flood management. In this paper we report on results from the 4 year PROTECT project which aims to optimise peatland restoration to support NFM benefits in the degraded peatlands of upland Britain. Field experiments based on a BACI analysis of over 20 peatland microcatchments along with hydrological and hydraulic modelling approaches have underpinned a series of key findings including: reductions in peak discharge and longer lag times for runoff from re-vegetated peatlands particularly associated with sphagnum growth; Reductions in peak discharge associated with optimised peat dams which allow partial drawdown between storm events; continued delivery of NFM benefit from restoration at timescales in excess of 10 years; and identification of a key role for dam permeability in optimising NFM benefits from drainage line blocking.

Taken together these data support the potential role of peatland restoration in NFM schemes and suggest that with careful optimisation synergies between the needs of peatland restoration and flood protection in headwater communities can be realised.